Bidirectional Forwarding Detection (BFD) is a network protocol used to detect faults between two forwarding engines connected by a link. BFD provides low-overhead detection of faults even on physical media that do not support failure detection of any kind, such as Ethernet, virtual circuits, tunnels, Pseudowires, and MPLS Label Switched Paths. BFD is defined in IETF RFC 5880, “Bidirectional Forwarding Detection”, D. Katz, D. Ward (June 2010); IETF RFC 5881, “BFD for IPv4 and IPv6 (Single Hop)”, D. Katz, D. Ward (June 2010); IETF RFC 5884, “Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs),” R. Aggarwal, et al. (June 2010); and IETF RFC 5885, “Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV),” T. Nadeau et al. (June 2010), the contents of which are incorporated by reference. Similarly, Carrier Ethernet includes Continuity Check Messages (CCMs) which are “heart beat” messages for Connectivity Fault Management (CFM) to detect connectivity failures in a Maintenance Association (MA). CFM is IEEE 802.1ag, Virtual Bridged Local Area Networks, Amendment 5: Connectivity Fault Management (2007) and ITU-T G.8013/Y.1731 (11/13) “OAM functions and mechanisms for Ethernet based networks,” the contents of which are incorporated by reference.
BFD, CCMs, etc. operate by sending periodic Continuity Check (CC) packets in associated sessions at a specific interval, and a failure to receive a set number of packets (e.g., three) leads to a determination that the session is down. Note, the transmission intervals may be at short intervals such as 10 ms or less to be able to detect data path failures within 50 ms. This short interval can be processor intensive on physical hardware. Larger Ethernet switches are specifically designed to handle numerous short interval CC sessions, e.g., over 10,000. However, it is difficult for smaller-scale Ethernet switches, such as Customer Premises Equipment (CPE) switches, to handle large number of short interval CC sessions. In fact, smaller-scale Ethernet switches are designed to handle several orders of magnitude less short interval sessions, e.g. 16 sessions vs. 16,000 sessions for a larger, Central-Office (CO) located Ethernet switch. Further, if there is protection, each connection requires two CC sessions, so these smaller-scale Ethernet switches may be able to handle only a small number of CC sessions (e.g., 8 sessions). One option to alleviate this limitation would be to add additional processing power in the smaller-scale Ethernet switches. However, this is not feasible due to cost concerns and the like.